Metagenomics studies are rapidly uncovering the compositional richness of microbial communities in diverse habitats ranging from the oceans to the human gut. While their fundamental role in our health and environment is undeniable, there is an urgent need for unravelling molecular mechanisms underlying the dynamics of these communities. This requires a combined experimental and computational approach. Recent studies (including those from the organisers’ and speakers’ labs) have underlined the success of such integrative approaches. For example, emergence of cell subpopulations (Varahan et al. eLife 2019, 2020), and long-term stability (Blasche, Kim et al. Nat Microbiol. 2021) through metabolic cross-feeding. As researchers world-wide map species dynamics in the ecosystems of their interest, this course will provide the necessary overview and tools for moving from cataloguing to identifying key interaction agents, especially metabolites. This will include integrating species and metabolite dynamics data, as well as leveraging the power of genome-scale metabolic models to predict community interactions.